The Influence of Ozone on the Nitrogen Circuit

Ozone has an intensive influence on the nitrogen circuit. At pH-values of more than 7, this means that especially in salt water with a pH-value of approximately 8.2 the toxic ammonia is oxidized to nitrate (NO3). And at pH-values at around 7, like in fresh water, the toxic ammonia is not oxidized, so that bacterial oxidation is required. But in any case the very toxic nitrite step will be oxidized by ozone to nitrate - this reaction being pH-value independant - so nitrite is oxidized to nitrate in fresh water as well as in salt water.This is most important as nitrite even in small traces is a poisonous compound for fish and invertebrates. As shown in the following diagram, the decrease of nitrite and ammonia is the faster the higher the ozone content is.

Regarding the oxidation of nitrite with ozone, there should be considered that ozone can help purifying aquarium water. If there should be a sudden peak in the nitrite concentration, not only the ozonizer should be switched to maximum, but above all, the reason should be sought within the aquarium system. It might be an unnoticed perishing animal or uncontrolled decay is processing at the bottom of the aquarium. Often it is the filter which has not been cleaned for some time and which possibly works without oxygen, i.e. under unaerobic conditions. Especially mechanical filters with high filtering velocity only work under aerobic conditions at first. The more solids they accumulate, the more oxygen is reduced within the filter. The aerobic biology is slowly repressed and the filter tips over to unaerobic conditions which usually results in extremely high nitrite peaks as the filter does no longer reduce nitrite but on the contrary, might even produce nitrite itself. So a mechanical filter should be cleaned frequently or even better, a biological filter should be used.

The influence of ozone on organic substances

The general degree of pollution of water containing organic material can be measured - even if the individual chemical compounds are unknown - by the biological oxygen demand, the B.O.D. value. The lower this value is, the better is the water quality. As shown in the diagram below, the organic load (B.O.D.) can also be reduced by ozone. Especially organic turbidity which results in a yellow colour of the water can be reduced by ozone. Yellow substances put strain on fish! Ozone is able to make water crystal-clear.

The influence of ozone on germs

A very important characteristic of ozone is it's degerminating action. Ozone can, even in very low concentrations, kill viruses, bacteria and other germs. It has to be pointed out, however, that within aquaria or other fish systems it can not be the aim of the ozone treatment to sterilize the water totally. This would result in a negative effect on fish and invertebrates.

Sander's Ozonizers for aquaria are especially designed for the use in home aquarium systems. Overwhelming cultures of germs are killed while avoiding total sterility. Operating this way, fish and invertebrates live in healthy and biologically active water.